Perplexity API: Building RAG Without Owning The Pipeline

Most teams that want grounded answers in their product set out to build a RAG pipeline: crawl, chunk, embed, store, retrieve, rerank, generate. The Perplexity API replaces all of that with one HTTP call. You send a question; you get back an answer with citations. For the first version of a product, it can compress a quarter of work into an afternoon.

The Sonar lineup

• Sonar small / large: fast, cheap, fine for short factual answers
• Sonar Pro / Reasoning: deeper synthesis with multi-step retrieval
• Specific model picks shift over time — read the API docs the day you build
• All Sonar models return citations, query rewrites, and the source URLs

Where you outgrow it

The API does not expose chunking, indexing, or reranking knobs. Your corpus must fit in the request context if you want it weighted, and that context is bounded. For a high-volume product where retrieval quality is the moat, you eventually move to your own pipeline — but you've shipped to real users in the meantime.

Minimal request shape

curl https://api.perplexity.ai/chat/completions \
  -H "Authorization: Bearer $PPLX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sonar-pro",
    "messages": [
      {"role": "system", "content": "You answer with citations. Refuse to speculate beyond sources."},
      {"role": "user", "content": "What changed in OSHA reporting rules in the last quarter?"}
    ],
    "return_citations": true
  }'

The big idea: the Perplexity API is the fastest route to a grounded answer in a product. Use it to ship; graduate when retrieval becomes your moat.